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go-mssqldb on Linux and macOS

The go-mssqldb driver is a pure Go library and compiles natively on Linux and macOS without external C dependencies. This article covers platform-specific configuration for authentication and certificates.

Installation

Installation is the same on all platforms:

go get github.com/microsoft/go-mssqldb

No ODBC driver, FreeTDS, or other C libraries are needed.

SQL authentication

SQL authentication works identically on Linux, macOS, and Windows:

sqlserver://<user>:<password>@<server>:1433?database=AdventureWorks2025

NTLM authentication

NTLM authentication is supported on all platforms. Provide a domain-qualified user name:

URL format

URL-encode the backslash in DOMAIN\user as %5C:

sqlserver://CONTOSO%5C<user>:<password>@<server>:1433?database=mydb

ADO format

The backslash in the user name triggers NTLM authentication:

server=<server>;user id=DOMAIN\<user>;password=<password>;database=AdventureWorks2025

The driver detects the backslash in the user name and uses NTLM automatically. No additional configuration is required on Linux or macOS.

Kerberos authentication

Kerberos authentication on Linux and macOS uses the krb5 package built into the driver. There are no external library dependencies.

Prerequisites

  1. A valid Kerberos configuration file. The default path is /etc/krb5.conf:

    [libdefaults]
    default_realm = MYDOMAIN.COM
    dns_lookup_kdc = true

[realms]
    MYDOMAIN.COM = {
        kdc = dc1.mydomain.com
    }

  2. The SQL Server instance must have a Service Principal Name (SPN) registered (for example, MSSQLSvc/<server>.mydomain.com:1433).

Connect with a keytab

Specify the keytab file path and Kerberos realm in the connection string:

sqlserver://<user>@MYDOMAIN.COM@<server>:1433?database=AdventureWorks2025&krb5-realm=MYDOMAIN.COM&krb5-keytabfile=/etc/<user>.keytab

Connect with a credential cache

First, get a ticket:

kinit <user>@MYDOMAIN.COM

Then connect by using the cached credential:

sqlserver://<user>@MYDOMAIN.COM@<server>:1433?database=AdventureWorks2025&krb5-realm=MYDOMAIN.COM&krb5-credcachefile=/tmp/krb5cc_1000

Kerberos parameters

Parameter Default Description
krb5-configfile /etc/krb5.conf Path to the Kerberos configuration file.
krb5-realm - Kerberos realm (for example, MYDOMAIN.COM).
krb5-keytabfile - Path to the keytab file.
krb5-credcachefile - Path to the credential cache file.
krb5-dnslookupkdc true Use DNS SRV records to find the Key Distribution Center (KDC).
krb5-udppreferencelimit 1 Maximum UDP message size before switching to TCP.

For more information, see SQL Server and Windows authentication.

Windows authentication (SSPI) isn't available

On Linux and macOS, Windows integrated authentication (SSPI / trusted_connection=yes) isn't available. Use one of the following alternatives:

Method Connection string
NTLM sqlserver://DOMAIN%5Cuser:password@host?database=db
Kerberos (keytab) sqlserver://user@REALM@host?database=db&krb5-realm=REALM&krb5-keytabfile=/path
Kerberos (cache) sqlserver://user@REALM@host?database=db&krb5-realm=REALM&krb5-credcachefile=/path
SQL auth sqlserver://user:password@host?database=db
Microsoft Entra ID sqlserver://host?database=db&fedauth=ActiveDirectoryDefault&encrypt=true&TrustServerCertificate=false (use azuresql driver)

Certificate configuration

On Linux and macOS, TLS certificates used with the certificate or serverCertificate parameters must be PEM-encoded files. The driver reads them by using Go's crypto/tls package directly.

System trust store

The driver uses the operating system's default certificate trust store. On Linux, this trust store is typically located at /etc/ssl/certs/ or /etc/pki/tls/certs/. On macOS, the system keychain is used.

To add a custom CA certificate to the system store:

Ubuntu/Debian:

sudo cp myca.crt /usr/local/share/ca-certificates/
sudo update-ca-certificates

RHEL/Fedora:

sudo cp myca.crt /etc/pki/ca-trust/source/anchors/
sudo update-ca-trust

macOS:

sudo security add-trusted-cert -d -r trustRoot -k /Library/Keychains/System.keychain myca.crt

Alternatively, use the certificate connection parameter to specify the CA certificate directly without modifying the system store:

sqlserver://<user>:<password>@<server>:1433?database=AdventureWorks2025&encrypt=true&certificate=/path/to/ca-cert.pem

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